Laserfiche WebLink
<br />CHAPTER THREE <br />FLOOD PROOFING MEASURES <br /> <br />Flood proofing may be designed to either reduce the number of times the building is flooded or limit the <br />potential damage to the building and its contents when it is flooded. There are three general approaches <br />to flood proofing: <br /> <br />. Raising or moving the building <br />. Constructing floodwalls or levees to stop floodwaters from entering the building <br />. Modifying the building and relocating contents to minimize flood damage <br /> <br />Specific types of flood proofing are briefly reviewed in this chapter. More detailed information regard- <br />ing the various flood proofing measures is available from the Floodplain Management Resource Center <br />at the Natural Hazards Center in Boulder, Colorado, referenced in Chapter Two. <br /> <br />~ ELEVATION <br />Elevation involves raising the building in place so that the lowest floor is above the flood <br />level for which flood proofing protection is provided. The building is jacked up and set <br />on a new or extended foundation. <br /> <br />Almost any structurally sound building can be elevated. Typically. the least expensive and easiest <br />building to elevate is a one-story frame building built over a crawl space that is 18 inches or higher. The <br />process becomes more difficult and expensive as different factors are added. such as a building with a <br />basement, a slab-on-grade building, a building constructed of brick or block, a multi-story building, or a <br />building with additions. <br /> <br />Property owners wishing to use this method should employ a contractor.to ensure that the building is <br />properly raised and a safe foundation is constructed. The elevated foundation must be able to withstand <br />erosion caused by floodwaters and the impact caused by ice and debris in floodwaters. It is also advis- <br />able to have the building inspected by a structural engineer prior to elevation to assess the structure's <br />ability to undergo elevation. <br /> <br />Buildings can be elevated on several different types of foundations, including raised foundation walls or <br />an open foundation. Elevating a building on an open foundation involves raising it onto piers, posts <br />(columns), or piles. Ifthe building is located in an area of coastal flooding, an open foundation is the <br />only way to safely elevate. If the building is subject to high-velocity floodwaters. significant water <br />depths, or potential erosion, the property owner should also consider having the building elevated on an <br />open foundation. Doing so will allow the waters to flow beneath the building and reduce potential <br />damaging impacts. <br /> <br />Elevation on Foundation Walls <br /> <br />Elevation on this type of foundation is normally used in areas of low to moderate water depth and <br />velocity. After the building is jacked up, existing foundation walls can be extended vertically using ma- <br />terials such as masonry block or poured concrete. The building is then set down on the extended walls. <br />While elevating on foundation walls is often the easiest solution to the problem of flooding, there are <br />several important considerations. The most important concern is that the original foundation and footing <br /> <br />7 <br />